Polycarbonate is widely used as a raw material in many different manufacturing sectors. It is believed that the demand for polycarbonate will increase significantly in the coming years and as such, improvements in the polymerization process are currently being developed.
Several processes for the production of polycarbonate are known, for example through the reaction of an aromatic dihydroxy compound and diaryl carbonate.
The aromatic dihydroxy compound and the diaryl carbonate are generally added in a molar ratio of 1:1 based on stoichiometric considerations, where at later stages in the polymerization, additional diaryl carbonate can be added to, for example, compensate for losses along the polymer process or to increase the endcap level in the final polycarbonate.
The relative amounts of both the aromatic dihydroxy compound and diaryl carbonate are generally controlled typically using mass flow meters, but even with this type of instrumentation, it is often found that significant deviations in the formulated monomer molar ratio exist. These deviations can alter the value of the endcap ratio in the final product and can therefore affect such properties as the heat aging stability of the polycarbonate.
Due to the increasing demands on polycarbonate production, the process for production of polycarbonate leaves ample room for improvement, in particular in view of the way the raw materials are introduced.